5(xy-x²)÷(xy/x²-2xy+y²)的-1次方×x²-y²/x² 其中x=1/2,y=-2/3

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5(xy-x²)÷(xy/x²-2xy+y²)的-1次方×x²-y²/x²其中x=1/2,y=-2/35(xy-x²)÷(xy/x

5(xy-x²)÷(xy/x²-2xy+y²)的-1次方×x²-y²/x² 其中x=1/2,y=-2/3
5(xy-x²)÷(xy/x²-2xy+y²)的-1次方×x²-y²/x² 其中x=1/2,y=-2/3

5(xy-x²)÷(xy/x²-2xy+y²)的-1次方×x²-y²/x² 其中x=1/2,y=-2/3
原式
=5x(y-x)× xy/(x-y)^2*(x+y)(x-y)/x^2
=-5y(x+y)
=-5*(-2/3)(1/2-2/3)
=-5/9